1. Field of the Invention
The present invention relates to electrical overcurrent protection devices, particularly electronic trip units for circuit breakers.
2. Description of Related Art
Circuit breakers are used in electrical distribution systems to protect electrical conductors and equipment against the effects of short circuits, ground faults, overloads and/or overcurrent conditions (hereinafter “abnormal current conditions”). Some circuit breakers have programmable electronic controllers for controlling operations of the circuit breaker. The programmable electronic controllers are known as electronic trip units and circuit breakers employing electronic trip units are known as electronic trip circuit breakers. The electronic trip unit monitors the conditions of an electrical circuit protected by its associated circuit breaker, and signals the circuit breaker to trip upon detecting an abnormal current condition. Some electronic trip units perform self-testing and provide an indication of detected problems with the trip unit.